The present invention concerns a heat exchanger for removing heat from cabinets which are utilized for the reception of electronic and/or electrical structural elements, especially such cabinets which are dust-tight and airtight. The heat exchanger includes a heat-receiving element adapted to be positioned inside the cabinet and a heat-dissipating element adapted to be positioned outside the cabinet, and both elements in combination form a closed cycle in which a liquid circulates, whereby a pump is proposed for the liquid circulation.
Heat exchangers are known in the prior art, having varying structures and various areas of utilization. The instant invention concerns the problem of heat removal from cabinets, in which are located electrical and/or electronic structural elements, such as, for example, transistors or thyristors. In a comparatively small space, such types of structural elements generate a relatively large amount of heat which must be dissipated outwards via a comparatively small cabinet space. Also in many instances the inside of the cabinet must be sealed airtight or dust-tight since the sensitive electronic or electrical structural elements must be protected from the influence of the atmosphere, especially from dust. Since, thereby in most cases cooling by means of air blown into the cabinet and exiting from the cabinet at a certain point is prohibited, the door of such cabinets are usually provided with ventilating cooling ribs at its inside and its outside. Even though this produces an air-cooling in which the entry of outside air into the inside of the cabinet is prevented, the heat transport obtained with such a door, however, is too small for a great many cases of utilization. The heat must be received at the door and cannot definitively be accepted in the cabinet at a point where it would be most advantageous. Additionally, the ventilators develop a relatively loud noise, which, especially in the otherwise very quiet electrical or electronic installations, is considered undesirable.
There are also known water-cooled thyristors which are screwed with a threaded portion into a block through which flows cooling water. The block and the thyristors are located in a cabinet. The heat moves from the thyristors via the block to the water. The water is guided by means of a mechanical pump to a cooler located outside the cabinet, for example, by means of a piston pump or a centrifugal pump, which is located in the water cycle. The water is then cooled and again returned to the block inside the cabinet. This system, in many regards, is disadvantageous. Such types of pumps and their component hose connections generally begin to leak after a certain period of time. In spite of constant maintenance of the pump, there exists the danger that cooling liquid will leak out during the interval between inspections. A loss of cooling liquid may result in the heat transport being either insufficient or nonexistent, which results in an overheating of the electrical or electronic structural elements. Leaking liquid, when there is a combination of unfavorable circumstances in the electrical installations, can result in short circuits. The hose systems, which are component parts of the liquid pump, become weak. In case where maintenance work on the pump and/or the hose systems requires the opening of the cabinet which houses the electronic structural elements, there exists the abovementioned danger of dust entering the cabinet. Mechanical pumps and their motor gears are expensive and develop relatively loud noises. The life span of storage of the motor gears is comparatively too short.